1. Field of the Invention
The present invention relates to a flow-through dip-spin coating process and system for applying a coating onto a workpiece.
2. Description of the Prior Art
Coatings are typically applied to workpieces in order to give the workpiece a desired property such as improved corrosion resistance, an improved appearance, improved lubricating properties and/or improved adhesive properties. Since coatings are less expensive than going to an upgrade of material like stainless steel from a basic carbon steel, coating processes have become very popular in the industry.
One method of applying a coating that is very popular is known as dip-spin coating. In this type of process, a mesh or porous basket filled with workpieces, such as fasteners, clamps, springs, O-rings, U-bolts, nails and screws, is immersed in a coating solution for a desired period of time. The basket is then removed from the coating solution and spun to eliminate excess coating solution by centrifugal force. The coated workpieces are then removed from the basket and sent to a curing stage where the coatings are hardened on the workpieces.
Dip-spin processes are most advantageous for small parts which can be coated in bulk and achieves precise, highly repeatable results, with transfer efficiencies as high as 98%. Additionally, dip-spin processes solve many environmental problems and allow many different types of coatings to be applied in an efficient and cost effective manner.
Conventional dip-spin coating processes have problems in that it is easy to get the coated and uncoated workpieces confused since the coated workpieces exit from the coating booth from the same side in which they entered as uncoated workpieces. Additionally, due to the care necessary to avoid the commingling of the coated and uncoated workpieces, the throughput of the coating process is not as fast as desired in that it is difficult to operate as a continuous process.